Prediction of mechanical properties of Chinese fir wood by near infrared spectroscopy

Mechanical properties and the visible and near infrared (NIR) (350–2500 nm) spectra obtained from longitudinal and transverse face of 155 small clear wood samples of Chinese fir (Cunninghamia lanceolata) were measured, and 103 of them were used to establish calibration models. Calibrations were tested on an independent set (52 samples). Differences between calibrations developed by using the longitudinal and transverse face were small. The calibrations developed by using NIR spectra (350–2500 nm) collected from transverse face were slightly inferior to those developed by using NIR spectra collected from longitudinal face. When reducing the spectral range to between 780 and 1050 nm, the calibrations developed by using NIR spectra collected from longitudinal face were slightly inferior to those developed by using NIR spectra collected from transverse face, and reducing the spectral range causes no decrease in the quality of the models developed using NIR spectra collected from transverse face. Partial lease square (PLS) modeling and test showed that calibrations developed using the visible and NIR spectra from transverse and longitudinal faces and calibrations developed by using the reducing spectral range (780–1050 nm) from the transverse face were moderate, and have a RPD range from 1.51 to 1.90. It is concluded that NIR spectroscopy can be used as an initial screening. __________ Translated from Journal of Northwest Forestry University, 2007, 22(5): 149–154 [译自: 西北林学院学报]     

Application of a Fourier transform—near infrared reflectance spectroscopy method for the rapid proximate analysis of the greenshell mussel (Perna canaliculus) and king (Chinook) salmon (Oncorhynchus tshawytscha)

Greenshell? mussel (GSM, Perna canaliculus) and king (Chinook) salmon (Oncorhynchus tshawytscha) are New Zealand's two major aquaculture species generating $380 million NZD in exports during the 2017–18 financial year. This study addresses the development and validation of a method based on Fourier transform—near infrared reflectance spectroscopy (FT‐NIRs) to determine proximate composition for both species to aid breeding‐, production‐ and consumer decisions. Rapid measurements of GSM (n = 176) were taken by FT‐NIRs and analysed by traditional wet chemistry ‘reference methods’ to develop calibration models for proximate composition (protein, moisture, fat, ash and carbohydrate). The predictive models for moisture (r² = 0.98, root mean square error of cross validation (RMSECV) = 0.314, residual prediction deviation (RPD = 6.47), protein (r² = 0.91, RMSECV = 0.295, RPD = 3.01)) and carbohydrate (r² = 0.87, RMSECV = 0.440, RPD = 2.78) in GSM performed well. Additional models based on 90 portions of salmon were developed to predict moisture (r² = 0.98, RMSECV = 1.02, RPD = 7), protein (r² = 0.96, RMSECV = 0.347, RPD = 5.08), fat (r² = 0.99, RMSECV = 1.09, RPD = 5.98) and ash (r² = 0.72, RMSECV = 0.05, RPD = 1.9). The predictive FT‐NIRs and reference methods were tested for short‐term and intermediate precision, which demonstrated that the repeatability of the predictive models was comparable to the reference methods. Proximate analysis of GSM and king salmon using FT‐NIRs was quick (minutes for sample preparation and analysis rather than days) and all components were assessed simultaneously. This provides a low‐cost short turn‐around method suitable for industry and research applications.     

秸秆腐解过程中结构的变化特征

应用尼龙网袋法和傅里叶变换红外光谱分析,研究玉米和大豆秸秆在3种不同试验地(葡萄园、桃园、农田)腐解过程中的结构变化特征,为秸秆还田措施提供理论依据。结果表明,玉米和大豆秸秆的官能团组成具有相似之处,但在3400、1640、1400~1460、1310、1000~1100 cm~(-1)处的吸收峰强度不同,稳定成分存在差异。腐解前后作物秸秆红外光谱吸收峰强度有所改变,随着腐解时间的增加,羟基、酰胺基、甲基、亚甲基和次甲基的含量逐渐降低,羧基增多,有机酸形成,碳水化合物、酰胺类化合物、糖类等逐渐分解。易分解的化合物(如脂肪族结构、酰胺类化合物和糖类)可直接进行分解,部分芳香类等难分解化合物则先分解为羧酸酯类(1725~1735 cm~(-1))、脂肪族类(1450~1460 cm~(-1))等中间产物后再进行分解。1560~1732 cm~(-1)处的肩峰与作物残体中有机酸有关。尿素对玉米秸秆的腐解具有促进作用,且与1310 cm~(-1)处的吸收峰变化有关。作物秸秆还田之后,会向腐植酸方向腐解,其结构变化在不同土地利用类型和干湿处理之间无明显区别(P0.05),与还田作物秸秆种类以及N含量有关。     

光热和水分条件对石灰岩山地侧柏人工林更新的影响

侧柏(Platycladus orientalis)是我国荒山造林、水土保持和涵养水源的重要常绿树种之一。它适应环境的能力强,栽培范围广,常被栽植于我国的石灰岩山地上。耐干旱瘠薄是公认的侧柏生态学特性之一,但是,侧柏幼苗和幼树的更新和生长受山地环境影响较大。通过热红外成像法移动观测山体光热能量的分配特征,利用SketchUP软件三维阴影分析的功能进行林窗日照和遮阴分布的计算机模拟,以及在山东省侧柏主要栽培区对山地林窗幼苗进行实地调查研究,结果表明:侧柏苗适合栽培在湿润而光照充足的立地上。山地阴坡和阳坡、山谷和山脊的光照和湿度的差异导致侧柏幼苗更新的变化,以至于一边因密度过大而出现严重的种内竞争,另一边因幼苗更新不畅而常出现林窗和空地。因此,需要通过适度的人工抚育和管理来解决该问题,以便在我国北方地区建立起稳定和完善的侧柏森林生态系统。     

红外玉米穗干燥试验研究

为研究红外辐射干燥条件下收获期玉米穗干燥的水分迁移规律,利用自制红外玉米穗干燥试验台对玉米穗进行了恒温和变温干燥试验,探讨了多种温度条件下玉米穗的红外辐射干燥特性及对干燥后玉米穗外观品质的影响规律。结果表明:初始含水率、干燥温度、干燥用时和辐射距离是影响玉米穗干燥效率和外观品质的主要因素;当恒温干燥玉米穗的干燥温度为58℃、辐射距离为150mm时,干燥速率达2.25%/h,且玉米籽粒的外观品质最好;变温干燥玉米穗时,较佳的干燥温度范围为55~65℃,且采用逐渐升温干燥时的干燥品质较好。本研究为研制红外辐射玉米穗干燥机研发奠定了坚实基础。     

近红外光谱法快速测定河南烟叶中木质素的含量

[目的]实现对河南烟叶中木质素含量的快速测定。[方法]首先改进了烟叶中木质素含量的测定方法,并对该方法测定的准确性进行了评定(对同一样品,8次平行测定的RSD值为3.58%),随后用此方法测定了河南地区95个初烤烟叶样品中的木质素含量,然后用近红外光谱仪采集相应的光谱,进行二阶微分处理和平滑预处理后,用偏最小二乘法和完全交互验证方式建立相应预测模型。[结果]试验建立的烟叶中木质素预测模型的相关系数达到96.13%,内部交叉检验均方根误差(RMSECV)为0.104,说明烟叶中木质素含量和近红外光谱之间存在较好的相关性。[结论]采用近红外光谱法可以快速预测河南烟叶中木质素含量。     

Comparison of Near Infrared Reflectance Spectroscopy with Combustion and Chemical Methods for Soil Carbon Measurements in Agricultural Soils

As interest in soil organic carbon (SOC) dynamics increases, so do needs for rapid, accurate, and inexpensive methods for quantifying SOC. Objectives were to i) evaluate near infrared reflectance (NIR) spectroscopy potential to determine SOC and soil organic matter (SOM) in soils from across Tennessee, USA; and ii) evaluate potential upper limits of SOC from forest, pasture, no-tillage, and conventional tilled sites. Samples were analyzed via dry-combustion (SOC), Walkley–Black chemical SOM, and NIR. In addition, the sample particle size was classified to give five surface roughness levels to determine effects of particle size on NIR. Partial least squares regression was used to develop a model for predicting SOC as measured by NIR by comparing against SOM and SOC. Both NIR and SOM correlated well (R² > 0.9) with SOC (combustion). NIR is therefore considered a sufficiently accurate method for quantifying SOC in soils of Tennessee, with pasture and forested systems having the greatest accumulations.Abbreviations SOC, soil organic carbon; NIR, Near Infrared Reflectance Spectroscopy; MTREC, Middle Tennessee Research and Education Center; RECM, Research and Education Center at Milan; PREC, Plateau Research and Education Center; PLS, Partial least squares.     

FTIR结合DWT鉴别研究六种不同植物来源的淀粉

利用傅里叶变换红外光谱(FTIR)结合离散小波变换(DWT)、主成分分析(PCA)和聚类分析(HCA)方法对甘薯、马铃薯、薯蓣、莲藕、豌豆、玉米淀粉进行鉴别研究,测试淀粉样品的红外光谱。结果表明,6种淀粉样品红外光谱相似,但在1 700~800 cm-1范围内,红外光谱的峰位、峰形及吸收强度差异明显。对此范围内的原始红外光谱进行离散小波变换,提取离散小波变换的第五尺度细节系数数据,进行主成分分析和聚类分析。离散小波的前3个主成分的累计贡献率为94.43%,主成分分析和聚类分析正确率为100%。研究表明,傅里叶变换红外光谱技术结合离散小波变换的方法可以鉴别不同植物来源的淀粉。     

6种动物毛发红外光谱特征分析

为探索红外光谱分析在动物毛发纤维司法鉴定领域的应用,采用傅立叶变换红外光谱(FTIR)法测定6种动物毛发纤维的红外光谱。结果表明,通过各自的特征峰比较可以鉴别出家兔和獭兔毛发纤维,但无法有效区别其他4种动物毛发纤维;通过傅立叶自去卷积技术对狐狸、水貂、安哥拉兔和羊毛发红外光谱进行解析,则可以鉴别这4种动物毛发纤维。     

猪肉新鲜度近红外检测仪的设计与应用研究

[目的]设计猪肉新鲜度近红外检测仪,并进行实例应用,为快速、无污染对猪肉作新鲜度检测提供新的方法。[方法]基于近红外技术,设计了近红外猪肉新鲜度检测仪。该仪器以短波近红外发光二极管为光源、硅光电二极管作为检测器,由近红外发射、Si-PIN驱动及电源电路3个模块组成。相比近红外光谱仪,该仪器结构简单、体积小、成本低、使用方便。用该仪器对自然放置的猪肉肉样进行连续3 d共12次检测试验,相邻2次测量对应的输出电压差在10 mV数量级以上。[结果]对不同存放时间的猪肉,输出信号有较好的区分度。试验数据可用于监测猪肉在鲜腐过程中的变化,结合简单的感观判别,可对猪肉作新鲜度分级。[结论]该研究可为猪肉新鲜度的无损检测提供一个新的方法。